There are many conditions which may result in a person becoming partially or completely edentulous (periodontal disease, an injury, etc.), which is commonly remedied today by dental implants. Dental implants are endosseous, being a “root” device that is usually made of titanium, where the implants are inserted into the jaw through the bone at the alveolar ridges, after which a healing period on the order of months is necessary for osseointegration. During this healing period the bone will grow in and around the implant to provide support.
The alveolar ridges are columns of bone, found on both the maxilla and the mandible, that surround and anchor the teeth within sockets known as alveoli. However, the alveolar bone quickly becomes atrophic in the absence of teeth, typically resulting in lack of sufficient bone mass for successful implantation. In the Maxilla, when sinus pneumatization decreases available bone after tooth loss, a sinus elevation procedure prior to implant placement is required to increase the amount of bone therein. The sinus lift procedure may be performed either through a lateral approach or a crestal approach.
In the crestal approach for a sinus lift procedure of the posterior maxilla (upper jaw), to which the improvements of the present invention is directed, a pilot drill may initially be used to create a small hole in the crestal cortex to reach the cancellous layer, and to form an implant insertion axis. The anatomical characteristics of the posterior maxilla, particularly the existence of its more spongy (cancellous) bone, enable it to successfully lend itself to undergo the ridge expansion osteotomy technique developed by R. B. Summers (see e.g., Summers, DMD, Robert B, “A New Concept in Maxillary Implant Surgery: The Osteotome Technique;” 1994; Summers, DMD, Robert B, “The Osteotome Technique: Part 2—The Ridge Expansion Osteotomy (REO) Procedure;” 1994; and Summers, DMD, Robert B, “The Osteotome Technique: Part 3-Less Invasive Methods of Elevating the Sinus Floor;” 1994).
The technique causes expansion of the pilot hole without further elimination of bone material, and generally compresses the bone and increases bone density, in the surgeon's favor. The technique uses a succession of conical expansion Osteotome tools having a gradual diameter escalation. The smallest caliber expansion Osteotome tool is inserted manually into the pilot hole, with pressing and rotating of the tool occurring until the desired depth is reached, or until further penetration is resisted, at which time gentle tapping using a surgical mallet on the Osteotome may cause it to reach the proper depth. Further use of successively larger Osteotome tools causes lateral compression that increases bone density and the size of the opening. The procedure is typically carried out by an oral surgeon using different calibers of Osteotomes that are constructed such that the initial diameter of a successively larger Osteotome is the same as the largest penetrating diameter of the previous conical Osteotome that was used, thereby providing a constant progression of increasing separation.
The procedure exhibits high success rates if the sinus membrane was not breached during the procedure, as discussed in the by Hernandez-Alfaro F, Torradeflot MM, and Marti C., title “Prevalence and Management of Schneiderian Membrane Perforations during Sinus-lift Procedures.” But a further consideration for the success of the implant concerns the impact of the Summers' diameter escalation on the crest of the alveolar ridge, when the ridge has undergone resorption producing a knife-edged shape, rather than its tall, rounded shape. The present invention offers various improvements to aid the oral surgeon, including Osteotome configurations and a method of use that reduce fracturing of the crest of the alveolar ridges—the most vulnerable area of the ridge during the osteotomy.